Found in a 1990s Popular Electronics, this circuit produces a tone on a small speaker. The keyer directly controls the power supply.
This circuit is from a Japanese magazine of 1973. The circuit is designed to withdraw the power...
This circuit generates a signal rich in harmonics that extends up to close to 1 GHz, serving for...
This circuit is from an old publication, from 1992, being indicated to test the old joysticks of...